Caterpillars' self-defence mimicry and camouflage

When you're easy pickings for any number of predators the ability to turn
yourself into a snake is a handy one. And that's what the snake mimic
hawkmoth caterpillar appears to be able to do. When threatened it will pull
in its legs and head and expand the back part of its body to make itself
resemble a snake. This snake's head is actually the tail of the caterpillar.